The present invention relates to a method and machine for producing a rigid packet of cigarettes.
In particular, the present invention may be used to advantage for producing what is known commercially as a pillow-type rigid packet of cigarettes, to which the following description refers purely by way of example.
In a pillow-type rigid packet of cigarettes of the type described, for example, in Patent Application WO 0043289A1, the front and rear walls each comprise a flat central portion, and two precreased lateral bands, each of which is curved with its concavity facing inwards to connect the central portion to the corresponding lateral wall along a relative sharp edge, and forms with the lateral wall a respective substantially obtuse dihedral angle.
Pillow-type packets of cigarettes are currently produced on standard cigarette packing machines which, however, have been found to produce good, but not superior, quality pillow-type packets.
It is an object of the present invention to provide a method of producing a rigid packet of cigarettes, designed to eliminate the aforementioned drawbacks and which at the same time is cheap and easy to implement.
According to the present invention, there is provided a method of producing a substantially parallelepiped-shaped rigid packet of cigarettes comprising a front wall and a rear wall opposite and substantially parallel to each other, and a pair of lateral walls opposite and substantially parallel to each other and substantially perpendicular to the front wall and the rear wall; the front wall and the rear wall each being connected to each of the lateral walls at a single respective sharp edge; the method comprising the steps of feeding a flat, substantially rectangular blank to a folding station, and folding the blank about an orderly group of cigarettes at the folding station; the blank comprising two main longitudinal crease lines, and a number of transverse crease lines defining, between said two main longitudinal crease lines, at least a first central panel eventually forming part of said front wall, and a second central panel eventually forming said rear wall; said two main longitudinal crease lines defining, on opposite sides of each said central panel, at least two respective lateral wings eventually forming part of said lateral walls; and the method being characterized by feeding the flat blank to a prefolding station upstream from said folding station; folding, at said prefolding station, the lateral wings of at least one said central panel about the respective main longitudinal crease lines; and restoring the blank to the flat configuration before feeding the blank to said folding station.
The present invention also relates to an automatic machine for producing a rigid packet of cigarettes.
According to the present invention, there is provided a packing machine for producing a substantially parallelepiped-shaped rigid packet of cigarettes comprising a front wall and a rear wall opposite and substantially parallel to each other, and a pair of lateral walls opposite and substantially parallel to each other and substantially perpendicular to the front wall and the rear wall; the front wall and the rear wall each being connected to each of the lateral walls at a single respective sharp edge; the packing machine comprising a folding station, conveying means for feeding a flat, substantially rectangular blank to the folding station, and first folding devices for folding the blank about an orderly group of cigarettes at the folding station; the blank comprising two main longitudinal crease lines, and a number of transverse crease lines defining, between said two main longitudinal crease lines, at least a first central panel eventually forming part of said front wall, and a second central panel eventually forming said rear wall; said two main longitudinal crease lines defining, on opposite sides of each said central panel, at least two respective lateral wings eventually forming part of said lateral walls; and the packing machine being characterized by comprising a prefolding station upstream from said folding station in the travelling direction of said conveying means; second folding devices for folding, at said prefolding station, the lateral wings of at least one said central panel about the respective main longitudinal crease lines; and third folding devices for restoring the blank to the flat configuration before feeding the blank to said folding station.